| Percussive-rotary drilling technique is one most effective drilling method, of which essence is a certain frequency percussive energy on the bit. There's a continual percussive force on the bit not only the static pressure and torque in percussive-rotary drilling technique. So percussive-rotary drilling is rotary drilling with percussive force. This technique can be divided into percussive-rotary drilling and rotary-percussive drilling as the difference effective of the rotary drilling and percussive drilling, and it is now generally referred to as percussive-rotary drilling.From the late 19th century, people had conceived of adding percussive force to the rotary drilling device to improve the drilling efficiency of hard rock. The hammer is the key technique to percussive-rotary drilling. In the last 100 years, from the initial idea to variety of hammers, the Percussive-rotary drilling technique and the concerned technique have got a rapid development. Nowadays, we have developed a variety of hammer. As the mechanism's difference, it can be divided into hydraulic hammer, pneumatic hammer, electric hammer, and so on. Hydraulic hammer and pneumatic hammer are both of the most popular hammers.With many years'research and development, the technical level and the practical using of the hammer which is used to percussive-rotary drilling have been very ripeness. There are still some defaults of the traditional hydraulic hammer and pneumatic hammer, such as:(1) Electric hammer's working parameters can not be adjusted down holeIf the traditional hammer down to the hole, the impacting energy and the impacting frequency would not be adjusted. The hammer would work as the station set on the ground, it could not be adjust as the stratum.(2) Can not be remote controlWhen the mud pump (air compressor) is on, the hammer will also be on and can not be control from the ground. If there is some emergencies that need to close the hammer we have to close the mud pump (air compressor) which may cause some accidents.(3) Can not get the situation of down holeThe traditional hammer can not get an accurate analysis of the situation such as:the empty impacting, waterways blocked, lock, etc. We just can judge these situations through experience. This situation can no longer meet the need of the drilling device's development. (4) Special requirements for mud pumpThe traditional hammers are usually driven by mud pump (air compressor). They need big mud pump (air compressor) pressure and flow to drive the hammers, the pressure and the flow are more than the normal using of the drilling. The big pressure and flow may cause some bad effects such as instability of the hole. There's also a special requirement for drilling fluid of the hydraulic hammer.(5) Limited application areasInfluenced by the drilling fluid's gravity and other factors, the traditional hammers are usually used to vertical drilling, there are some limits when they are used to horizontal directional drilling and directional drilling. Because the hammers are driven by the drilling fluid or air, so it can not be used in some special drilling where has no use of drilling fluid.This dissertation combines the research project "Research of electric hammer and its correlative techniques" of China geological survey, research on the electric hammer's control system, performance test system, sealing system etc. The main contents of the dissertation are as follows.(1) System principle analysis and structural design of the electric hammerThe electric hammer, electrokinetic cell powered, is based on electromagnetic theory, it can be remote control through the ground. The whole structure can be divided into 3 parts:MH/Ni cells capsule, control system capsule, electromagnetic percussion device capsule. The different capsules are connected by hermetically sealed cable etc.The electric hammer has no special requirements to the correlative devices and it is driven by MH/Ni cells, without special requirements for drilling fluid etc. So the electric hammer can be conveniently used to horizontal directional drilling and directional drilling. Especially, some place that can not using drilling fluid.(2) Remote control system of the electric hammerResearch the application of mud pressure pulse in remote control system of the electric hammer. Take mud pressure pulse as ground-down-hole communication system's transmission channel. Design the coding system on ground and the decoding system down hole, establish the communication protocol and develop remote control system, which is based on the mud pressure pulse, of the electric hammer.(3) Calculate and analyze the electric hammerBuilding the model different mode of action of electromagnetic devices, simplified model, and make the relevant calculations. According to calculations, the double-acting electromagnetic devices can get a bigger impacting energy and higher impacting frequency. Therefore, the system use the double-acting electromagnetic devices as the final choice. Establish the kinetic model of the double-acting electromagnetic device and do the dynamic calculation and analysis of it. According to calculations, optimize the control system and get the formula of the impacting energy and impacting frequency. Simulate electromagnetic field distribution of the electromagnetic devices, as the result the magnetic field strength is much bigger in the center of the coil. While, at both end of the coil, the magnetic field strength decay quickly. So the Magnetism Material should be place in the center of the coil.(4) Design the Control system of the electric hammerIntroduce hardware design and the remote control command's resolution process of the decoding system down-hole. The remote control command is made up of mud pressure pulse. Study the circuit theory and hardware design of the power supply module, USB module, detection module, CPU module, etc. These modules make up of the down-hole monitoring system. Design a full bridge circuit, which is based on IGBT, of the electromagnetic device. Design the driven circuit of the full bridge circuit, the driven circuit is based on IR2110 and the 555 timer. Do a detail analysis of the bridge circuit and the driven circuit. Design a signal processing circuit of the control system, which is used to avoid signal confusion and protect the bridge and the driven circuit. After test, the circuit can control the electromagnetic device well. Design the software of the control system.The control system can detect working conditions such as pressure, leakage, temperature, impacting frequency, etc of the electric hammer and save these parameters to the memory. Judge the down-hole accidents such as:system leakage, lock etc and deal these accidents. Make a great improvement of the system's automation.(5) Design the performance test system of the electric hammerStudy the general program of the performance test system and design the performance test system following the electric hammer's requirements.Syncretize the photoelectric method and the coefficient methods'characteristic and design a new method to accomplish the impacting energy's measurement. Design the impacting frequency's detecting method using proximity switch. Analyze the detecting methods of the temperature, speed, working voltage, working current, etc. Design the subordinate computer based on C8051F340 and host computer based VC, both of them connected through the USB bus. Introduce the software programming of the USB communication and design the communication protocol.(6) Performance test result of the electric hammerThe electrokinetic cell of the electric can be continuous working about 100 minutes. The battery of the control system can continuously work about 540 minutes and can work about 760 minutes in standby mode. If surrounded by drilling fluid, temperature of the electromagnetic device may rise about 40℃after working 100 minutes. The electromagnetic device can still work normally in this situation. After working 100 minutes, temperature of the IGBT may rise about 25℃, it even has no influence to the property of the IGBT. The greatest stroke of punch of the electric hammer is about 30mm. The range of the impacting energy is from 3J to 11.8J. The range of the impacting frequency is from 5Hz to 8.5Hz.Through the study of this dissertation we can get the following innovation points:(1) Propose the electric hammer based on electromagneticAccording the shortage of the traditional hammer in the actual using, propose the electric hammer which is based on electromagnetic theory. Design the performance test system of the electric hammer.(2) Adjust the impacting energy and the impacting frequency down hole The impacting energy and the impacting frequency can be adjusted down hole. It is the intrinsical difference between the electric hammer and the traditional hammer. The impacting frequency can be adjusted through changing the period of the power on. The impacting energy can be adjusted through changing the duty cycle. The electric hammer can work in different performance parameter, such as big impacting energy and high impacting frequency, big impacting energy and low impacting frequency, small impacting energy and high impacting frequency, small impacting energy and low impacting frequency. This is very important for the drilling of different hardness rocks.(3) Remote controlThe electric hammer's working state such as work on, closure, impacting energy's adjustment and impacting frequency's adjustment can be adjusted through the remote control command form the ground. It can improve the drilling efficiency in complex stratum.In conclusion, remote control system, control system, performance test system, machinery and mechanical seal system of the electric hammer all realize the desired effect and achieve the preplanned research targets, the electric hammer goes well. The impacting energy and the impacting frequency have large gaps between the electric hammer and the traditional hammer. Because the technology has just been involved in research so there is still tremendous development space and potential. Considering the technology has just been involved in research, there is still tremendous development space for the further development. Finally, according to the test results, several tips were brought forward for the continue study.
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